1. Field of the Invention
The present invention relates in general to object modeling, and in particular to a system and method for determining structure and motion from two-dimensional (2D) images for multi-resolution object modeling.
2. Related Art
In the computer vision field, it is very desirable to determine motion and structure from 2D images. One of the first methods to determine motion and structure and solve this problem involved assuming an orthographic camera projection model. Three views were necessary to recover the motion and structure from point correspondences with this method. A full perspective projection model was used, and thus two views were sufficient from point correspondences. After this method was introduced, other approaches have been proposed to solve the problem using either linear or nonlinear methods.
Recently, the use of uncalibrated images has been used. The main motivation to use linear projection models is in order to avoid the non-linearity of perspective projection and the numerical instabilities incurred during structure from motion (SFM) analysis that arise due to this non-linearity. When the field of view subtended by the object/scene of interest is small, the errors due to the linear approximation can be negligible. Thus, the approximation errors (potentially negligible) are traded off against the numerical instabilities (potentially severe for narrow field-of-view).
Although both full perspective and its linear approximation (affine, weak perspective and orthographic projection models) are used in structure from motion, currently they are only used separately. In other words, images are assumed to be obtained under the same projection model. Therefore, what is needed is an efficient system and method for determining structure and motion from two-dimensional (2D) images of different projection models for multi-resolution object modeling. What is also needed is a system and method that performs multi-resolution object modeling from different projection models that produces stable results.
Whatever the merits of the above mentioned systems and methods, they do not achieve the benefits of the present invention.
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention, in general, is embodied in systems and methods for determining structure and motion of an object using multiple sets of images from different projection models of the object for multi-resolution modeling of the object. In addition, the present invention is embodied in a method for deriving a novel fundamental matrix from multiple images of the object and using parameters of the fundamental matrix to digitally recover a model of the object.
Namely, two-dimensional (2D) images of a three-dimensional (3D) object are obtained from multiple sets of views with different projection models, such as from a full perspective view and a weak perspective views. The fundamental matrix embodies the epipolar geometry between a full perspective view and a weak perspective view. The systems and methods of the present invention preferably uses the derived fundamental matrix together with the 2D image information of the full and weak perspective views to digitally reconstruct the 3D object and produce results with multi-resolution processing techniques. These techniques include recovering and refining motion parameters and recovering and refining structure parameters. The results can include, for example, 3D positions of points, camera position between different views, texture maps, and the like.